Vegetation treatment

ABSTRACT

A method is provided for inhibiting plant growth by inducing hypothermia by applying a treating substance to summer annual weeds and grasses. Susceptible undesirable plants will be killed by this treatment, while non-susceptible desirable plants will not be adversely affected by this treatment. Compressed carbon dioxide may be applied to other summer grasses to cause the grasses to become dormant. An apparatus is provided for inducing hypothermia in undesirable plants by applying a treating substance. A canister capable of housing gas may be provided. A valve may be provided to control the amount and pressure of gas dispensed from the canister.

STATEMENT OF PRIORITY

This application is a continuation-in-part application of, and claimspriority to, U.S. application Ser. No. 12/499,841, filed Jul. 9, 2009now abandoned, which claims priority to U.S. Provisional PatentApplication No. 61/079,513, filed Jul. 10, 2008, the entire disclosuresof each of which are incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for treatingvegetation. Specifically, the invention relates to a method andapparatus for the selective killing of plants, or inhibiting plantgrowth, by inducing extreme hypothermia. The hypothermia is induced byapplying a compressed gas, such as carbon dioxide, to selected plants.

BACKGROUND OF THE INVENTION

The presence of undesired plants on a lawn or in a garden can bedifficult to treat and frustrating for owners. Removing certainundesired plants while maintaining other plants is a problem on farms,golf courses, and residential yards. Golf course owners may re-sod anentire green or fairway if stubborn summer perennial grasses like sometypes of Bermudagrass grow on the green or fairway. Re-sodding is a verycostly solution for managing the invasion of summer perennial grasses.

Traditional herbicides do not always effectively treat weeds. As moreplants are treated with chemical weed killer, plants may develop atolerance to herbicides, thereby increasing the amount of herbiciderequired and decreasing efficiency of the treatment. Certain grasses andweeds are difficult to kill and traditional herbicides often requiremultiple applications before plants die. The use of herbicides may oftencause turf to discolor. Also, many herbicides are not intended for usewhen the temperature reaches 85° F. or warmer. If herbicides are used inwarm temperatures, desired grasses often die along with unwanted plants,or the desired grasses may experience extreme stress. As such,traditional herbicides may not effectively remove weeds at the point inthe weed growth cycle when weeds grow the most and the quickest withoutalso causing harm to desirable grasses.

Chemical herbicides are harmful to people and the environment. Weedtreatments may pose a risk for an individual dispensing weed killer ontoa treatment surface since herbicides often contain poisonous chemicals.A chemical residue may remain on a treated area, thereby posing a riskto small children and pets. Harsh chemical weed killers are detrimentalto the environment since toxins may leech into the soil and drain intowater runoff. Such detrimental effects have prompted increasedgovernmental regulations limiting the type and amount of chemicalsutilized to treat weeds and crops.

Accordingly, a need exists for an apparatus and method of vegetationtreatment which selectively treats weeds and other undesirable plantswhile allowing desirable plants to remain.

SUMMARY OF THE INVENTION

In accordance with the present invention, an apparatus is provided toselectively treat undesirable plants. Specifically, the apparatus may beused to deliver a treating substance or material such as compressed gasor liquid to selected summer annual or perennial grasses, and/or tocertain summer annual or perennial weeds. The apparatus may include acanister capable of containing a compressed treating substance ormaterial like a compressed liquid or gas. For instance, the canister maycontain carbon dioxide or other gases, either alone or as a mixture. Thecanister may contain traditional or organic herbicides. A dip tube maybe provided within the canister for drawing the treating substance fromthe canister. A length of tubing and/or hose may be provided having afirst end and a second end. The first end of the tubing may be connectedto the canister. The treating liquid or gas may flow from the canisterthrough the tubing. The second end of tubing may be connected to anozzle, including any type of spray tip. The nozzle may include anopening through which the treating fluid, such as compressed carbondioxide gas or liquid, may flow. A valve may be provided along thelength of tubing to control the amount and the rate at which thetreating liquid and gas is dispensed from the canister. The valve mayinclude a regulator. The valve may be activated by a gear or triggerlinkage connecting the valve to a trigger. The gear and trigger may alsobe connected by a spring that closes the valve when the trigger isreleased. A delivery mechanism may also be provided. The deliverymechanism may be positioned along the length of tubing and provides forregulating the application of treating material to a selected area.

A method is provided for treating vegetation by inducing hypothermia byapplying a hypothermic treating substance or material. For instance,carbon dioxide gas may be applied to selected vegetation to inducehypothermia. Also provided is a method for treating vegetation byapplying a treating substance capable of creating a hypothermic responsein selected plants. For instance, a substance or material may be appliedthat is a compressed liquid or gas, or even a solid state. Any gas maybe used in connection with the present invention, including inert gas.When compressed gas is utilized, the rapid expansion of the gas causescooling, and in the case of carbon dioxide, a mixture of carbon dioxidegas and solid carbon dioxide (also known as dry ice) may be dispensed.Depending on conditions, water vapor may also condense as ice or froston the treated areas. The cold temperature created by this rapidexpansion may be utilized to kill undesirable plants or grasses or causethem to become dormant. In a specific application, a method is providedto induce hypothermia by discharging compressed carbon dioxide to one ormore summer plants or grasses. The carbon dioxide may be applied for aselected amount of time at a selected pressure. Examples of summerplants that may be killed by hypothermic treatment with carbon dioxideinclude, but are not limited to, crabgrass, henbit, corn speedwell,seedling white clover, annual bluegrass, chickweed, common dandelion,lespedeza, goosegrass, foxtails, and barnyardgrass. Compressed carbondioxide may be applied to selected summer grasses to cause the grassesto become dormant. Examples of summer grasses which may become dormantinclude but are not limited to Bermudagrass, Centipedegrass, St.Augustine grass, Zoysiagrass, and Bahiagrass. The method describedherein does not harm cool season grasses such as Fescue, and is unlikelyto control perennial white clover, buckhorn plantain, or curly dock. Insome embodiments, the application of compressed carbon dioxide gas maycause certain summer grasses to die and certain other summer grasses tobecome dormant.

The present invention may also be used to treat summer weeds. Carbondioxide gas may be applied to one or more selected summer weeds for aselected time, pressure, flow rate and/or spray pattern, to kill atleast a portion of the weeds. The presently claimed invention exploitsthe relative cold-hardiness of desired plants, such as fescue grass, toallow for the removal of interspersed non-desirable plants, includingcertain summer grasses such as crabgrass and certain summer weeds suchas lespedeza, and to slow or stop the growth of invasive summerperennial grasses such as some types of Bermudagrass. Examples of summerweeds that may be treated include crabgrass, spurge, knotweed, annualbluegrass, chickweed, common dandelion, seedling, white clover, henbit,cord speedwell, and lespedeza.

In some embodiments, the present invention may include the applicationof adjuvants. Such adjuvants induce the crystallization of water presentin the plant. When ice crystallization is sufficient to disrupt thecellular integrity of the vegetation, the result is cell death. Anadjuvant of this invention may be any substance used for cloud seeding.

Ice is used to protect frost-susceptible crops like strawberries fromsubfreezing (e.g., below 32° F.) temperatures by controlling thenucleation of ice crystals. In particular, certain bacteria known tocarry ice nucleating proteins, such as Pseudomonas syringae, may beapplied to induce ice crystallization on the surface of a plant forprotection. Alternately, genetically engineered variants of Pseudomonassyringae lacking the ice nucleating protein may be introduced todisplace the ice-nucleating native bacteria in order to reduce thelikelihood of ice crystallization. For this invention, adjuvants mayalso include certain bacteria known to carry ice nucleating proteins,such as Pseudomonas syringae, as well as an ice nucleating protein, forthe purpose of inducing ice nucleation within the plant, resulting inthe death of all or part of the plant. An adjuvant of this invention canalso be silver iodide, Erwinia herbicola, E. ananas, E. uredovora,Xanthomonas campestris, X. campestris pv. translucens, P. fluorescens,P. viridiflava, P. chlororaphis, P. putida, Enterobacter agglomerans,Ent. taylorae, Saccharomyces cerevisiae, Fusarium acuminate, Fusariumavenaceum, and Erwinia ananas. Other adjuvants of this invention caninclude but are not limited to, methanol, ethanol, propanol,isopropanol, butanol, and/or isobutanol, as well as any citrus extracts.

The apparatus and methods of the present invention may be utilized inorganic gardening and/or organic farming practices, and in conventionalfarming.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic elevational view of an apparatus for applyingcompressed carbon dioxide gas to summer grasses and summer weeds inaccordance with the present invention.

FIG. 2 shows large crabgrass (2-3 tiller) control seven days aftertreatment. Fisher's Protected Least Significant Difference (LSD)=5.9.

FIG. 3 shows large crabgrass (3-4 tiller) control seven days aftertreatment. LSD=5.6.

FIG. 4 shows percent control of 2-3 tiller large crabgrass versus poundsof CO₂ applied.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, an apparatus 10 for treatingplants is provided. As shown in FIG. 1, a canister 20 capable of storingand dispensing a treating substance or material may be provided. Thecanister 20 may contain treating substances under pressure and/ortemperature control such as a compressed gas, compressed liquid, or evena solid. Generally, a compressed treating material or substance within acontainer is stored in liquid form. The liquid may be stored under ahigh amount of pressure. Alternatively or in addition, any gas may beused in connection with the present invention, including inert gas. Amixture of gases may be used in connection with the present invention.For example, gases stored with the canister 20 may include carbondioxide, oxygen, nitrogen, air, or other similar gases. The canister 20may contain a dip tube 22 to draw the treatment substance such as liquidcarbon dioxide from the canister 20 and particularly from the bottom ofthe canister. The canister 20 may be constructed in a variety of sizes.For instance, the canister 20 may be a smaller size so it may behand-held or the canister 20 may be a larger size and towed by avehicle.

The present invention may also provide for a valve 40. The valve 40 mayinclude a regulator. The valve 40 may be connected with the canister 20or manufactured onto or as a part of the canister. The valve 40 maycontrol the amount and rate of treating substance dispensed from thecontainer 20 and may include an adjustable knob or handle 42 to controlthe rate of treating substance released from the canister 20. The valve40 may control the rate of treating substance released from the canister20 to control the rate of delivery to a selected treatment area. In oneembodiment, the valve 40 may be a ball valve or other valve capable ofrestricting the pressure of the treating substance or gas released fromthe canister 20. Optionally, a remote trigger capable of actuating thevalve 40 may be provided.

The canister 20 may optionally include a release valve to vent thecontents of the canister 20. The release valve may include a regulator.Opening the release valve permits gas to flow out of the container froma region of high pressure within the canister 20 to a region of lowpressure external to the canister 20. The gas is released quickly fromthe container to enable the gas to cool upon expansion. Under certainconditions, carbon dioxide that is being released rapidly will form amixture of solid carbon dioxide (also known as dry ice) and gaseouscarbon dioxide. The canister 20 may be positioned so that a releasevalve is oriented away from the surface to be treated.

A length of dispensing tubing and/or hose 30 having a first end and asecond end may be provided. The first end of the tubing 30 may beconnected with the canister 20. Specifically, the tubing 30 may beconnected with the valve 40, which in turn may be adjacent to or part ofthe canister 20. In one embodiment of the invention, the tubing isinsulated. In certain applications, the canister 20 may contain a liquidhaving a boiling point lower than the ambient air outside the canister.As the liquid is expelled from the canister 20 it is exposed to theambient temperature and pressure. The rapid volume or pressure change asthe compressed gas enters ambient conditions causes the temperature todrop (PV=nRT). The discharge of the canister 20 happens too quickly forthermal equilibrium to be established. Depending on conditions, eithergas or a mixture of gas and solid carbon dioxide may be dispensed. Thepresent invention utilizes this non-adiabatic expansion to imparthypothermic damage to the targeted plant. The tubing 30 may include orbe connected with a dispensing nozzle, for example, in the form of anoutput dispensing nozzle tube 88 located along or at the distal portionof the tubing 30 and having a nozzle so mounted or manufactured or afree end of the nozzle tube 88 thereby providing, for example, a spraywand.

The tubing 30, as well as dispensing nozzle tube 88, may be rigid orflexible and must have an appropriate pressure rating. For increasedefficiency and protection of the user, the tubing 30, as well as nozzletube 88, may be insulated. If the temperature of the treating substanceincreases while in the tubing 30 or 88, the resultant pressure increasemay exceed the design specifications of some types of tubing. Therefore,tubing 30 and 88 should be made from appropriate materials. Nonlimitingexamples of tubing include ¼″ stainless steel tubing and ¼′ braidedstainless steel tubing.

The nozzle 50 may be positioned directly at the second end of the lengthof tubing 30 or may be connected by additional tubing, such as thenozzle tubing 88. Specifically, the nozzle 50 may be positioned alongthe output nozzle tube 88. The nozzle 50 may cooperate with the valve 40for dispensing treating substance to a selected area. In one embodiment,the treating substance may be dispensed through the nozzle 50 toselectively treat one or more undesirable plants which may includeweeds, grasses, summer annual grasses, and/or summer annual plants.Compressed gas or liquid stored within the container 20 may flow throughthe tubing 30 and is released into the ambient environment throughnozzle 50. The nozzle 50 may include any type of spray tip, such as aspray nozzle, a high velocity nozzle, a length of capillary tubing, orother similar nozzle. The nozzle 50 may contain a needle or capillarytube through which the treating substance may exit the apparatus 10. Forinstance, once compressed gas leaves the nozzle 50, the released gaswill expand rapidly. The size of the opening of the nozzle 50 and/orneedle may be selected based upon the type of treating substance such asgas, size of canister 20, and length of tubing 30 used as well asstorage pressures and temperatures. The nozzle 50 may have a smallopening, for example, a zero degree nozzle.

The nozzle 50 may be enclosed in an insulated cone or box, 52, to directthe application of the gas and to insulate the hypothermicmicroenvironment. The use of an insulated cone 52 may increase theefficiency of the treatment by one or more orders of magnitude.Increasing the efficiency means that the LD₅₀ (lethal dose to 50% ofplants) is decreased from 2 pounds of CO₂ per plant to less than 0.2lbs/CO₂ per plant. The insulated box or cone may be made of layers ofmaterials comprising or consisting of plastic, insulating foam, and/ormetal.

A delivery control mechanism 80 may be provided to selectively dispensea treating substance from the canister 20. The delivery mechanism 80 maybe positioned along the length of tubing 30 between the canister 20 andthe nozzle 50. Specifically, the delivery mechanism 80 may be positionedbetween the canister and the output tubing 88. The nozzle 50 may bepositioned at the distal end of the output tube 88. The deliverymechanism 80 may include a handle 82 for ease of use. The deliverymechanism 80 may include a delivery valve 84 to control the rate atwhich the treating substance is dispensed from the canister 20 throughthe nozzle 50. The delivery valve 84 may include a regulator. Thedelivery mechanism 80 may also include a trigger, grip activator, orother actuation mechanism 86. Activating the trigger 86 may cause aselect amount of treating substance to be released from the canister 20.Specifically, activation of the trigger 86 may actuate a trigger linkage90, which in turn actuates the delivery valve 84. Optionally, a springis provided to close the delivery valve 84 upon release of the trigger86. In one embodiment, the delivery valve 84 may include a ball valvecapable of regulating the amount of treating substance released. Uponsqueezing the trigger 86, the treating substance may be discharged fromthe canister 20 through the output tube 88 and the nozzle 50 at the endof the output tube 88 to spray a selected area. In one embodiment, aremote trigger capable of actuating the delivery valve 84 is provided.The output tube 88 may be configured to apply gas or treating fluid at aselected distance from plants. In one embodiment, the output tube 88 mayapply gas to ground level. In one embodiment, a delivery mechanism 80including a trigger 86 and output tube 88 may be provided to facilitateshort burst spraying.

A vapor canister 60 may be provided to increase the amount of watervapor in the ambient air. The vapor canister 60 may include a vaporsensor or humidity detector 62 to alert the user when the moisturecontent of the surroundings is low or at, below, or above a selectedlevel. The vapor canister 60 may be attached beside the canister 20 ofcompressed gas or the vapor canister 60 may be separate from thecanister 20. For example, the efficacy of the compressed gas to destroyplants may be improved if the ambient air is moist. Accordingly, a vaporcanister 60 may be used to supplement the dry air, thereby increasingthe effectiveness of the compressed gas to treat plants. Locations wherethe use of a vapor canister 60 may be desirable include desertenvironments.

A transporter 70 may be used to transport the canister 20 to desiredlocations or during treatment. The transporter 70 may include a cart ortrolley having one or more sets of wheels so that a user may move thecanister 20 to or at a desired location. The wheels may be large spokewheels, pneumatic tires, or other similar wheels.

The present invention may have a plurality of configurations. Thepresent invention may be used as a small hand-held aerosol container tospray weeds for private or residential use. One benefit of a small sizedcontainer is that the container may be recycled or more easilytransported.

The apparatus 10 may be larger so that a larger area of land can betreated. For instance, the canister 20 may hold at least five pounds ofcompressed gas or treating substance. Tubing 30 for use in conjunctionwith a five pound canister 20 may be thick and durable hose or tubing.Examples of suitable hose include high pressure hoses used on trucks andheavy equipment, stainless steel braided hoses, and stainless steeltubing. Optionally, one or more shoulder straps may be provided tofacilitate ease of use of the apparatus 10 by an individual. In oneexample, the canister 20 may be made available to consumers with theshoulder strap and transporter. The canister 20 may be recycled and/orrefillable.

Even larger canisters 20 may be utilized. For instance, canisters 20 maybe configured to hold five, ten, fifteen, twenty, twenty five, or thirtypounds (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,21, 22, 23, 24, 25, 26, 27, 28, 29, 30), or even more, of compressed gasor treating substance. Larger canisters, for instance such as ten poundcontainers or even larger, may treat an area of one hundred to fivehundred square feet or larger, or may be used to spot-treat over an evenlarger area. The containers may be purchased along with a suitabletransporter 70.

Larger commercial applications may also be provided. In lieu of portablecanisters 20, tanks may be utilized. Tanks may accommodate fifty or morepounds of compressed gas. Large tanks may exceed fifty pounds but anoperator should be able to appropriately position the tank or at leastthe spray nozzle or nozzles to treat a desired section of land. Thetank, a suitable delivery mechanism and a suitable transporter may bepositioned on a unit towed behind the operator. For instance, a smallboom may be used to dispense the treating fluid so that the operator maycover a greater amount of land. The boom unit may dispense compressedgas to one or more residential yards. A large tank for extended sprayingmay also be provided on a tow trailer behind the tank. For instance, thetow trailer might be attached to a vehicle such as a truck. The operatormay ride the apparatus while simultaneously spraying a selected area.The tank may be mounted directly onto a vehicle. The vehicle may haveseveral hundred feet of hose and the hose could be pulled across a yardto spray a particular spot. A hose reel may be employed to store thetubing. Larger, towable tanks may be utilized in agricultural settingsto treat larger tracts of land. Providing insulating cones, boxes, orother semi-enclosed insulation will improve the efficiency ofapplication on any scale. Further, the compressed gas may be nebulizedor atomized as it is applied to a selected area.

The present invention includes a method to treat certain vegetation suchas selected grasses or weeds to either kill selected vegetation or toinduce dormancy in certain vegetation. The susceptibility of plants tocold may be harnessed to selectively determine which plants survive. Oneor more treating substances, for instance, compressed gases are sprayedonto a plant, thereby stunting plant growth. Optionally, the treatingsubstance may include a gaseous carrier of an herbicide. In oneembodiment, the treating substance may include compressed carbondioxide. Other gases that may be applied for treating plants includeair, nitrogen, oxygen or any mixture of gases and such gas or gasmixture may be selected to treat different plants or to matchtemperature or gas properties of the gas or gas mixture to differentplants. Application of compressed gas, such as carbon dioxide, may killplants which are not resistant to cold temperatures. Those plants thatare resistant to cold temperatures survive the hypothermic treatment.

Different types of plants may be treated with the present invention. Ingeneral, plants that become dormant during colder weather may bereferred to as “perennial,” while plants that regenerate from seed aftera cold season are called “annuals.” Annuals typically only grow duringwarm months. Accordingly, annual plants may be referred to as “warmseason plants” whereas perennial plants may be referred to as “coolseason plants.”

Ground temperature may influence plant growth to a greater extent thanair temperature. For example, ground temperatures may drop to as low as−40° F. or even −60° F. and grasses or plant life adapted to coldtemperatures can survive. Above-ground parts of plants may die while theroots remain viable under the soil. If the roots remain at anappropriate temperature, the plant will survive cold temperatures.Summer annual weeds and grasses are usually killed off in the firstautumn frost and are very susceptible to cold temperatures. Accordingly,summer annual grasses and weeds are particularly vulnerable tohypothermic treatment with compressed gas. In general, summer annualplants, including weeds and grasses, die when treated with compressedgas, while summer perennial grasses become dormant. One such example ofa summer perennial grass that becomes dormant in colder temperaturesincludes some types of Bermudagrass. Alternatively or in addition,summer annual plants, such as grasses or weeds, may be harmed fromhypothermic treatment. Application of treating substance may eradicateone or more plant species that encroach upon an area, particularly intropical or subtropical climates. The use of hypothermic treatment maybe utilized in connection with organic farming and/or organic gardening.

The ability to selectively kill at least a portion of certain plantswhile other plants remain unharmed is highly desirable. The presentinvention provides a method to inhibit plant growth by applying atreating substance, including for instance compressed carbon dioxidegas, to a plant surface. Release of compressed gas from a canister 20causes a decrease in temperature near a selected plant surface. Watervapor may freeze and be deposited on the plant surface, thereby frostingthe plant. In one embodiment, the compressed gas may cause ambient airto reach a temperature of as low as −40° F. For example, the compressedgas can be used to drop the temperature of ambient air to a temperaturewithin −40° F. and 32° F. As an additional example, the use of carbondioxide and/or dry ice may cause ambient air temperature to drop toapproximately −109° F. and some plants may survive after being exposedto such low temperature. Plants resistant to colder temperaturessurvive, while plants susceptible to cold temperatures may be killed orbecome dormant.

Grasses may include plants that flourish during warm weather months butdie or become dormant in cooler weather months. Examples of summerannual grasses which may be treated include but are not limited tocrabgrasses (Digitaria spp.), goosegrass (Eleusine indica), foxtails(Setaria spp.), and barnyardgrass (Echinochloa crusgalli). Summerperennial grasses which become dormant in cooler weather months includebut are not limited to some types of Bermudagrass, Centipedegrass, St.Augustine grass, Zoysiagrass, and Bahiagrass.

In some embodiments of this invention, a method is provided for treatingsummer weeds. A weed may include an undesirable plant. A weed may alsoinclude a plant that grows in an undesirable location. Summer weeds areplants that grow during warm weather months and die or become dormant incooler weather. Examples of summer annual weeds which may be treatedinclude but are not limited to Spurge, knotweed, and lespedeza.

The rate, volume, and/or moisture content of treating substancedispensed from the container may be regulated. Treating substance withinthe container is dispensed over a selected length of time. In certaininstances, application of short bursts of treating substance may bedesirable; in other instances, it may be desirable to provide acontinuous application of treating substance to one or more selectedtargets.

In some embodiments, the present invention provides an apparatus forinducing hypothermia in a plant, comprising: a canister for containing ahypothermia-inducing substance; a valve cooperating with the canisterfor controlling the amount of the hypothermia-inducing substancedispensed from the canister; and a nozzle cooperating with the valve fordispensing the hypothermia-inducing substance from the canister onto theplant to induce hypothermia in the plant. In the apparatus of thisinvention, the canister can include a dip tube, a remote trigger,wherein the remote trigger actuates the valve and/or a spray tip on thenozzle, in any combination. The apparatus can also include a nozzle thatis enclosed in an insulating cone, insulating container, insulatingvessel or insulating structure.

In particular embodiments, the apparatus of this invention can beadapted to dispense the hypothermia-inducing substance in a metereddose. Dispensing of the substance in a metered does would beaccomplished by using a microcontroller to cause the valve to operate ina preprogrammed manner, for example to be open for a fixed amount oftime, or for example to be opened for iterative time exposures. Inanother embodiment, the apparatus can be adapted to notify the operatorof the preprogrammed dispensing by showing different colored lights(e.g., red and green). The apparatus can have a dose counter to displayhow many doses have been dispensed and/or how many doses are remaining.In further embodiments, the apparatus of this invention can be adaptedto contain a compressed gas (e.g., a gas held under pressure at or above600 psi). In a specific embodiment, the compressed gas can be compressedcarbon dioxide gas.

In embodiments in which the apparatus of this invention has a nozzlethat is enclosed in an insulating cone or other insulating container orvessel or structure, carbon dioxide gas can be dispensed at a dose rangefrom about 0.05 lb/square foot to about 0.2 lb/square foot. Inparticular embodiments, the carbon dioxide gas can be dispensed at adose of about 0.15 lb/square foot.

Furthermore, embodiments of the apparatus of this invention include anapparatus comprising a radio frequency identification (RFID) tagoperably associating the nozzle and the canister.

The present invention also provides methods, which can employ theapparatus of this invention as well as any other apparatus suitable forcarrying out the methods described herein. Thus, in one embodiment thepresent invention provides a method for inducing hypothermia in one ormore plants, comprising applying a hypothermia-inducing substance thatis contained under pressure to the one or more plants at a selected flowrate for a selected amount of time to induce hypothermia effective tokill at least a portion of the one or more plants. In variousembodiments, the hypothermia-inducing substance can be compressed carbondioxide gas. A range of flow rates for the methods of this invention isfrom about 0.25 lbs/minute to about 10 lbs/minute and in someembodiments the flow rate can be from about 0.5 lbs/minute to about 4.0lbs/minute. A range of application times for the methods of thisinvention is from about 0.5 seconds to about 2 minutes.

Also provided herein is a method for inducing hypothermia in undesirableplants in a population of plants comprising desirable and undesirableplants, comprising applying a hypothermia-inducing substance that iscontained under pressure to the population of plants at a selected flowrate for a selected amount of time to induce hypothermia effective tokill at least a portion of the undesirable plants in the population.

The methods of this invention can be employed to induce hypothermia in,e.g., summer annual plants. Nonlimiting examples of summer annual plantsinclude grasses, weeds, invasive plant species and any combinationthereof. Additional nonlimiting examples of a plant of this inventioninclude crabgrass, annual bluegrass, seedling white clover, henbit, cornspeedwell, common chickweed, common dandelion, goosegrass, foxtails,barnyardgrass, spurge, knotweed, lespedeza, a herbicide resistant plant,a glyphosate resistant plant (e.g., Palmer amaranth or pigweed) and anycombination thereof. In particular embodiments, the plant is crabgrass.

The methods of this invention can further comprise the step of applyingan herbicide to the one or more plants or to the population of plants.Nonlimiting examples of herbicides of this invention include glyphosate(also known as RoundUp), which is a nonselective herbicide, as well asDrive 75, Acclaim, Speedzone and Target, which are selective herbicides.

In further embodiments, the methods of this invention can comprise thestep of applying an ice nucleation-inducing substance that results inice nucleation in the one or more plants or in the undesirable plants inthe population of plants. Nonlimiting examples of the icenucleation-inducing substance of this invention include silver iodide,an ice nucleating bacterium (e.g., Pseudomonas. syringae), an icenucleating protein and any combination thereof.

In methods employing the application of an herbicide or an icenucleation inducing substance, these can be applied before, after and/orsimultaneously with the application of the hypothermia-inducingsubstance. In some embodiments, both an herbicide and an icenucleation-inducing substance can be applied before, after and/orsimultaneously with the application of the hypothermia-inducingsubstance. In some embodiments the herbicide and/or ice nucleationinducing substance, if soluble, can be dissolved in the hypothermiainducing substance (e.g., carbon dioxide). Thus, in various embodiments,the hypothermia-inducing substance, the herbicide and the icenucleation-inducing substance can be applied from the same apparatus(e.g., combined in the canister or from separate canisters) or appliedfrom separate apparatuses.

In the methods of this invention, the application of thehypothermia-inducing substance can result in frost on the one or moreplants.

In the methods of this invention, the one or more plants to be targetedfor hypothermia can be present among row crops (e.g., corn, soy beans,cotton). Thus, the methods of this invention can be carried out in aconventional farming or organic farming environment.

In particular embodiments of this invention, a method is provided, ofkilling all or part of a plant, comprising applying to the plant carbondioxide gas under pressure from an apparatus comprising: a canister forcontaining the carbon dioxide gas, a valve cooperating with the canisterfor controlling the amount of the carbon dioxide gas dispensed from thecanister; and a nozzle cooperating with the valve; said nozzle beingenclosed in an insulating cone wherein the carbon dioxide gas is appliedat a flow rate and for a period of time effective to kill all or part ofthe plant. Such a method can further comprise applying an adjuvant tothe plant, which can be silver iodide, an ice-nucleating bacterium(e.g., Pseudomonas syringae), an ice-nucleating protein and anycombination thereof. In such a method the plant to be killed, all or inpart, can be crabgrass.

As used herein, “a,” “an” or “the” can mean one or more than one. Forexample, “a” cell can mean a single cell or a multiplicity of cells.Also as used herein, “and/or” refers to and encompasses any and allpossible combinations of one or more of the associated listed items, aswell as the lack of combinations when interpreted in the alternative(“or”). Furthermore, the term “about,” as used herein when referring toa measurable value such as an amount of a compound or agent of thisinvention, dose, time, temperature, and the like, is meant to encompassvariations of ±20%, ±10%, ±5%, ±1%, ±0.5%, or even ±0.1% of thespecified amount.

EXAMPLES Example 1

One application of compressed air may be sufficient to stunt or killcertain summer annual grasses and certain summer annual weeds. Duringone informal experiment, application of compressed air to a patch ofcrabgrass approximately 1 square foot in size slowed plant growth assoon as 24 hours after treatment. After a period of 48 hours thecrabgrass had started to discolor. After 72 hours most of the crabgrasshad disappeared while the surrounding Tall Fescue, a cool season grass,remained unchanged. Similar experimental results have been obtained whencompressed gas is applied to other unwanted plants in the presence ofFescue. Compressed air applied to Bermudagrass slowed growth after aperiod of 24 hours. The Bermudagrass appeared dormant after 48 hours.After 72 hours the grass appeared completely dormant. The Bermudagrassdid not show signs of re-growth for a period of approximately five daysafter the initial application of compressed air during extremely hot,humid summer conditions (over 95° F. and 100% humidity).

Example 2

Greenhouse-grown crabgrass plants were treated with the prototypecontaining either an 8002 flat fan nozzle (which was measured to release2 pounds of CO₂ per minute) or with an 8004 flat fan nozzle (whichreleases 4 pounds of CO₂ per minute), to determine if the rate ofapplication affects the percent control achieved. Control means killingor death of the plants as determined by visual observation. The percentcontrol is a visual rating of the treated plant compared to an untreatedcontrol plant. In other words, is the percent of plant death. Trialswere conducted in triplicate.

As shown in FIG. 2, treatment for 30 seconds with the 2 lb/min nozzleresults in 40 percent control, while treatment with the 4 lb/min nozzlefor 15 seconds results in 42 percent control; in both cases one pound ofCO₂ was dispensed. Similarly, treatment for 15 seconds with the 2 lb/minnozzle results in 17 percent control with 0.5 pounds of CO₂ dispensed,while treatment with the 4 lb/min nozzle for 5 seconds results in 12percent control with 0.3 pounds of CO₂ dispensed. From this study, itwas concluded that for crabgrass, the total amount (dose) of CO₂ appliedcorrelates with % control. See FIG. 4, which graphs % control vs. CO₂dose with two different application rates.

In the data presented in FIG. 3, the crabgrass plants are larger. Theyare at the 3-4 tiller stage, whereas the plants in the data presented inFIG. 2 were 2-3 tiller plants. The CO₂ application controlled both plantsizes well, and with the larger plants the same trend of percent controlcorresponding to the total pounds of CO₂ applied was observed. In bothcases the LD₅₀ is over 1 pound CO₂/plant.

Most commercial herbicides achieve 80% control or better. The prototypeused 2 pounds of CO₂ to achieve this level of control for one 6″ plant.At the 2 lb/plant dispensing rate, a commercial 25-lb cylinder of CO₂would only treat 10 plants; clearly efficiency increases were needed tocreate a viable backpack sprayer system. An insulating cone was attachedaround the nozzle with the expectation of possibly achieving a modestincrease in efficiency, perhaps cutting the CO₂ requirement by 20-50%.

Quite surprisingly, upon addition of this insulating cone, it waspossible to achieve 80% control or better by spraying only 0.15 lbs ofcarbon dioxide on field-grown 2-3 and 3-4 tiller plants. These resultswere repeated with a 1-lb/min nozzle sprayed for 9 seconds and a3-lb/min nozzle sprayed for 3 seconds. Unexpectedly, a greater thanten-fold reduction in the CO₂ usage was achieved (Table 1). The resultsare especially remarkable since field-grown plants (treated with theinsulated design) are usually harder to kill than greenhouse-grownplants that were treated with the non-insulated design.

It will be recognized by those skilled in the art that changes ormodifications may be made to the above-described embodiments withoutdeparting from the broad inventive concepts of the invention. It shouldtherefore be understood that this invention is not limited to theparticular embodiments described herein, but is intended to include allchanges and modifications that are within the scope and spirit of theinvention as set forth in the claims.

TABLE 1 Control with the initial non-insulated prototype and themodified insulated prototype designs non-insulated stage % control (lbsCO₂) Insulated (lbs CO₂) 2-3 tiller greenhouse 75 2 3-4 tillergreenhouse 87 2 2-3 tiller field 80+ 0.15 3-4 tiller field 80+ 0.15

What is claimed is:
 1. In an apparatus for inducing hypothermia in aplant, comprising: a canister for containing a hypothermia-inducingsubstance; a valve cooperating with the canister for controlling adispensed amount of the hypothermia-inducing substance from thecanister; and a nozzle cooperating with the valve for dispensing thehypothermia-inducing substance from the canister onto the plant toinduce hypothermia in the plant, the improvement comprising aninsulating structure enclosing the nozzle, thereby reducing theeffective amount of the hypothermia-inducing substance needed to inducehypothermia in the plant.
 2. The apparatus of claim 1, wherein thecanister includes a dip tube.
 3. The apparatus of claim 1, furthercomprising a remote trigger, wherein the remote trigger actuates thevalve.
 4. The apparatus of claim 1, wherein the nozzle includes a spraytip.
 5. The apparatus of claim 1, adapted to dispense thehypothermia-inducing substance in a metered dose.
 6. The apparatus ofclaim 1, wherein the canister is adapted to contain a compressed gas. 7.The apparatus of claim 6, wherein the gas is compressed carbon dioxidegas.
 8. The apparatus of claim 7, wherein the carbon dioxide gas isdispensed at a dosage range from about 0.05 lb/square foot to about 0.2lb/square foot.
 9. A method of killing all or part of a plant,comprising applying to the plant carbon dioxide gas under pressure fromthe apparatus of claim 7, wherein the carbon dioxide gas is applied at aflow rate and for a period of time effective to kill all or part of theplant.